3 years ago

Multifunctional Phenanthroimidazole Derivatives to Realize High-Performance Deep-Blue and White Organic Light-Emitting Diodes

Multifunctional Phenanthroimidazole Derivatives to Realize High-Performance Deep-Blue and White Organic Light-Emitting Diodes
Caijun Zheng, Qingxiao Tong, Juewen Zhao, Hui Lin, Xiaohong Zhang, Silu Tao, Xiaoyang Du, Guang Li
Deep blue emitters with high quantum yield, good stability, and multifunctionality are still the key technology for white organic light-emitting diodes (WOLEDs). To address this, two multifunctional deep-blue materials 4-{2-[4′-(1,4,5-triphenyl-4,5-dihydro-1H-imidazol-2-yl)-biphenyl-4-yl]-3a,11b-dihydro-phenanthro[9,10-d]imidazol-1-yl}-benzonitrile (CPD) and 4-(2-{4′-[1-(4-tert-butyl-phenyl)-4,5-diphenyl-4,5-dihydro-1H-imidazol-2-yl]-biphenyl-4-yl}-3a,11b-dihydro-phenanthro[9,10-d]imidazol-1-yl)-benzonitrile (tCPD) based on phenanthroimidazole units are designed, synthesized, and characterized. Both the materials show high quantum yields and good stabilities. The deep-blue fluorescent devices using CPD and tCPD as emitters show maximum external quantum efficiency (EQE) of 5.80% and 4.71% along with Commission Internationale de I'Eclairage (CIE) coordinates of (0.15, 0.07) and (0.15, 0.09), respectively. Two-color based WOLEDs are demonstrated by doping Ir(MDQ)2acac into CPD and tCPD with a low doping concentration, both devices show high EQEs of 16.4% and 16.6% and CIEs of (0.49, 0.34) and (0.48, 0.32), respectively. Furthermore, three-color based fluorescence/phosphorescence-WOLEDs (F/P-WOLEDs), with reasonable exciton management, are fabricated to enhance exciton utilization and improve device performance. CPD-based WOLED shows high efficiencies of 49.4 cd A−1, 53.5 lm W−1, 19.0%, and CIE coordinate of (0.46, 0.46). With the same structure, tCPD-based device also shows high efficiencies of 40.6 cd A−1, 47.2 lm W−1, 19.4% along with CIE coordinate of (0.43, 0.45). These results are among the best of reported deep-blue OLEDs and F/P-WOLEDs. Two novel multifunctional phenanthroimidazole derivatives are used to construct high performance white organic light-emitting diodes (WOLEDs). Step-wise energy transfer takes place to enhance exciton utilization and improve device performance. As a consequence, high external quantum efficiency of over 19% and power efficiency of over 50 lm W−1 with stable electroluminescence spectra are achieved for WOLEDs.

Publisher URL: http://onlinelibrary.wiley.com/resolve/doi

DOI: 10.1002/adom.201700498

You might also like
Discover & Discuss Important Research

Keeping up-to-date with research can feel impossible, with papers being published faster than you'll ever be able to read them. That's where Researcher comes in: we're simplifying discovery and making important discussions happen. With over 19,000 sources, including peer-reviewed journals, preprints, blogs, universities, podcasts and Live events across 10 research areas, you'll never miss what's important to you. It's like social media, but better. Oh, and we should mention - it's free.

  • Download from Google Play
  • Download from App Store
  • Download from AppInChina

Researcher displays publicly available abstracts and doesn’t host any full article content. If the content is open access, we will direct clicks from the abstracts to the publisher website and display the PDF copy on our platform. Clicks to view the full text will be directed to the publisher website, where only users with subscriptions or access through their institution are able to view the full article.